To develop a coordinated program for uniform preclinical testing and evaluation of monoclonal antibodies and immunoconjugates (drugs, toxins, radioisotopes) in several test systems prior to entry into clinical trials. Monoclonal antibodies submitted for evaluation under this contract will have been subjected to a minimum level of characterization and been shown to have at least one of the following characteristics: 1 Specificity against a defined molecule (a growth factor), but need not necessarily have been characterized by immunohistochemistry. Features indicating ptoential usefulness as a tumor marker by immunoassay. Specificity for tumors by preliminary immunohistological testing against major human organs (spleen, liver, kidney). It is anticipated that 20 to 30 monoclonal antibody preparations will be evaluated annually by immunofluorescent and/or immunoperoxidase histochemistry.